Excavation

Date 3 July 2017 - 30 September 2017

Event ID 1039779

Category Recording

Type Excavation

Permalink http://canmore.org.uk/event/1039779

NC 0366 2784 (NC02NW 2) A programme of structural conservation and excavation was carried out, 3 July – 30 September 2017. In order to address unstable walling on the S side of the broch, rubble was removed from the interior of the broch and the stair gallery on the S side cleared of debris. The outer wall face on the S side was partially taken down, its

footing consolidated by installing a concrete plinth dowelled to the bedrock, and reinstated in its original arrangement.

During the rubble removal, it was observed that the collapse debris within the broch was semi-structured, suggesting that the majority of the rubble related to the collapse of the upper parts of the broch tower. There was little evidence that this debris had been disturbed since this collapse.

Deposits relating to the use and destruction of the broch were encountered and excavated. On exposure of the scarcement ledge, a thick deposit of charcoal, primarily comprising small roundwood and similar to that which provided a date of 2025±30 BP (SUERC-36728) during previous works (DES 2011, 96–7) was encountered. This layer of burning was found to be extensive across the interior parts of the broch, and many of the stones of the internal wall showed evidence for heating to high temperatures. It therefore seems probable that the interior of the broch was burnt on abandonment; further 14C dating will be undertaken to establish with confidence the date of this event. The charcoal layer was sampled on a grid in order to assist with the analysis and interpretation of its composition.

Beneath the charcoal layer, evidence for at least three phases of hearth construction were found, each associated with laminated flooring deposits suggesting repeated refurbishment. The hearths comprised flagstones of the local sandstone, surrounded by edge-set kerb stones. In the NE

quadrant, a clay floor contained a knocking stone or mortar, full of carbonised cereal grains suggesting that it was in use at the time of the conflagration. The floor deposits themselves comprised wet organic clays, interleaved with bands of peat ash, probably representing hearth rake-out.

Excavation was carried out in the 9 o’clock intra-mural cell, finding evidence for grain storage in the form of a mass of carbonised cereal grains, as well as refurbishment of a flagstone floor with layers of beach sand. Excavations in the westernmost guard cell showed that this cell was much disturbed, though a compact organic clay in the directly overlying the bedrock floor may represent in situ deposits. No artefacts were recovered from either cell. Excavation of the rubble infill of the 12 o’clock gallery was carried out in order to relieve the weight over a void in the outer wall face on the S side of the broch, and facilitate removal of the outer wall face in this area for the installation of a supporting plinth. These works uncovered the stairs, 13 steps from the bedrock leading clockwise to the remnants of

the first floor landing. In clearing rubble from the ruinous S broken wall end prior to stabilisation and consolidation, the remnants of a further intra-mural gallery were exposed, suggesting the presence of a further gallery in the original ground floor plan of the broch on the W side.

Within the interior of the broch, compensation for the steeply sloping bedrock by the builders of the broch has resulted in the construction of a curving passage, reminiscent of a souterrain, formed by a lining wall in front of the bedrock and the inner face of the broch on the E side. This lower space was floored with flagstones; a rotary quern was found lying at its base.

A large artefact assemblage was recovered from the excavations, including numerous finely carved stone lamps or cups, c50 finished and unfinished spindle whorls, rotary quern stones, strike-a-lights, a complete antler weaving comb and fragments of others, bone pins, iron pins, a complete copper alloy ring-headed pin and a sizeable assemblage of decorated ceramics. A range of iron objects was also recovered, including a probable axehead, though most await identification. The large animal bone assemblage included representation of a range of domesticates as well as cetacean, seal and red deer. The post-excavation analysis programme is now under way.

Archive: NRHE (intended)

Funder: Historic Environment Scotland, Heritage Lottery Fund, SSE Communities Fund, and Pilgrim Trust

Graeme Cavers, John Barber, Nicholas Johnstone and Gordon Sleight – AOC Archaeology Group

(Source: DES, Volume 18)